Vol. XXVII. 



iqii 



J Hardy, A Red Euglena. 219 



the opportunity to — thus specially directed — examine the 

 living cells more carefully had passed, but in any case the red 

 colour and the abundance of granular matter would have made 

 this task a difficult one. 



The red form en masse sooner decomposed than the green, 

 and gave off a sickening odour unlike the other, and also more 

 rapidly accumulated fungoid growths. 



Experiments with the habitat were rather inconclusive, 

 owing to the recent succession of cool summers in southern 

 Victoria largely checking the appearance of Euglena of any 

 kind ; but during the one summer when this was practicable 

 a quantity of red Euglena transferred to one of the adjacent 

 dams — the nearest, about 100 metres distant — either suc- 

 cumbed or failed to multiply, as, months subsequently, ex- 

 amination of the water revealed not a single cell. Nor did 

 any visible increase take place that season in the amount of 

 green forms that were liberated in the small pool. Associated 

 with the Euglena of this pool were some diatoms, desmids, &c., 

 and some anaboena, all in small quantity. 



I have, at perhaps inordinate length, taken pains to describe 

 the environment and habitat of this red form in the hope that 

 further attention will be given to similarly coloured Euglenae 

 elsewhere ; but, even if the stability of E. sanguinea holds good, 

 the shorter flagellum and other characters are, I think, sufficient 

 to establish E. rubra as a species. 



Description. 



Size. — Motile cell, excepting flagellum, up to 200 ^/. by 

 60 i-i. diam. ; encysted, up to 80 /<. ; flagellum slightly shorter 

 than body. 



Form. — Cylindro-fusiform, but less fusiform than E. viridis ; 

 anterior end rounded ; posterior end rather suddenly reduced, 

 and continued as a short cylindrical extremity, with rounded 

 tip. Frequently with greatest girth behind centre. 



Markings. — Cuticular furrows or ridges about i ^<. apart, 

 and forming, with the longitudinal median line, an angle of 

 30° or less, and making less than one complete spiral turn round 

 body. 



Eye-spot. — Situated as in E. viridis, but occulted by grains 

 and red colour of cell. 



Gullet and vacuoles. — Imperfectly observed. 



Origin of flagellum, and relation of flagellum to eye-spot, 

 not satisfactorily observed. 



Nucleus. — Situated a little behind middle, within greatest 

 girth. 



Colour. — In living organism, ruby red, usually under low 

 power of magnification, filling the cell — all but the posterior 



